Supplemental Cash Flow Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Non-cash investing and financing activities:
Fixed assets acquired with accounts payable or accrued liabilities	$ 13,199	$ 12,202
Issuance of promissory note in exchange for sale of equity method investment	0	54,154
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	12,817	9,020
Investing cash flows from finance leases	0	10,896
Financing cash flows from finance leases	0	45,773
Right-of-use assets obtained in exchange for lease obligations:
Operating leases	25,545	21,066
Finance leases	$ 0	$ 51,064